B12 deficiency is common in people with Inflammatory Bowel Disease or chronic diarrhea. Over time, severe prolonged deficiency can lead to pernicious anemia - the inability of the body to process and store vitamin B12.

Although oral supplements are available, they may not be appropriate for those with pernicious anemia or scarring in their ileum due to Crohn's disease. Other forms of B12 supplements are sublingual, nasal gel, and subcutaneous or intramuscular injections. Sublingual B12 supplements may not be SCD compliant, so check the ingredients carefully.

For more information on B12 deficiency, pernicious anemia and supplements, See: